Starter circuit - solenoid not disengaging BUT solenoid not the problem

[svenhanne]

long story short, I have an 81 SC with a hot start relay wired before the starter solenoid. Previous owner installed push start button, I am taking it back to original - lots of dodgy wiring that I am undoing bit by bit. Now I have the following phenomenon:

1. start car with push-start button that is wired separately from ignition straight to hot start relay, works perfect
2. start car with ignition switch, car starts but solenoid stays engaged
3. start car with rigged up positive feed straight to hot start relay while wiring from ignition switch still connected - same as 2, car starts but solenoid stays engaged

to better understand why the solenoid is not disengaging I wired a red LED in parallel with the starter solenoid after the relay and yes, when solenoid doesn't disengage, there is 12V positive despite (scenario 2) switch no longer in start position and (scenario 3) cable no longer attached to hot start relay

my thought is that either the CSV or the fuel pump relay get excited/switched by ignition current and feed power from other source through after ignition/wire no longer active

ignition switch electrics brand new and tested with multimeter and work as they should...

anyone any idea where to look next? ...help...

[Porboynz]

You have to wonder what came first, the push button or the problem it overcomes with the self latching hot start relay. Suspect that hot start relay self latching. You are sure the ignition switch is working correctly and only applying 12V to the relay in the crank position. Remember that relay needs just milliAmps to operate whereas the starter solenoid needs many Amps. Consider removing the relay and wiring and starting over. Frustrating stuff, good luck.

[svenhanne]

Thanks Porboy, I thought about it but figured in that case starting via direct feed to trigger side of relais (same point the ignition switch connects to) wouldn't work either - however have swapped the relay out and unfortunately still same problem... help much appreciated though

[svenhanne]

and yes, didn't mention it earlier, the series of faults and fixes around this are long - first I removed an aftermarket alarm that drove me nuts and reconnected the circuits it had put its tentacles into, the ignition wire (yellow No 50 feed) was actually disconnected inside the ignition switch, so I reconnected that - and half of the ignition wires were in the wrong places...so sorted that...then found that some prick had bridged permanent 12V and switched 12V behind the dash...and half of the connectors on light switch were on wrong pins...good part is the car runs (as much as it can without windscreen, dashboard, steering wheel and seats) and the lights all do what they are meant to... but the starter is doing my head in (yes, I could always go back to push button but where is the fun in that..?)

[James Brown]

there are a couple threads here about the same subject. might even be the PO

[svenhanne]

thanks, will have another look, couldn't find one that matched my symptoms.

[T77911S]

por gave you about the best advise you could get.
when someone has butchered the wiring like the PO did there is not a lot we can do.

you can try to isolate the start wire.
unplug the 14 pin connector and see if it does it.
work backwords to the ign sw.
check back of ign sw to see if power is on the start pin with and without the wire connected.

you can connect a light bulb in place of the starter to see when it goes out instead of always starting the car.

check the rear window defog circuit. it gets ground thru the solenoid.

[boyt911sc]

Originally Posted by svenhanne

long story short, I have an 81 SC with a hot start relay wired before the starter solenoid. Previous owner installed push start button, I am taking it back to original - lots of dodgy wiring that I am undoing bit by bit. Now I have the following phenomenon:

1. start car with push-start button that is wired separately from ignition straight to hot start relay, works perfect
2. start car with ignition switch, car starts but solenoid stays engaged
3. start car with rigged up positive feed straight to hot start relay while wiring from ignition switch still connected - same as 2, car starts but solenoid stays engaged

to better understand why the solenoid is not disengaging I wired a red LED in parallel with the starter solenoid after the relay and yes, when solenoid doesn't disengage, there is 12V positive despite (scenario 2) switch no longer in start position and (scenario 3) cable no longer attached to hot start relay

my thought is that either the CSV or the fuel pump relay get excited/switched by ignition current and feed power from other source through after ignition/wire no longer active

ignition switch electrics brand new and tested with multimeter and work as they should...

anyone any idea where to look next? ...help...

Svenhanne,

Try to make a sketch of the existing wiring diagram of the fuel pump circuit including the starter. It might take a couple of drawings before you get them right but without this schematic, you are looking for a miracle to get someone find the solution to this problem. I saw your post with zero reply and back off. No way I could understand and analyze your wiring set up by your description.

If you could not figure out how to make the sketches, then don't expect to fix it. Unless you have a clear understanding of the current configuration, good or bad, you are better off starting from scratch and follow the original or factory wiring. If you could post the sketches, we could give you a better advise. Right now, everyone including yourself are just guessing. You could read and analyze wiring schematics more precisely than describing the set up merely by words which would be inadequate or insufficient. Keep us posted.

Tony